Food security is necessary for civilization. Food security, in turn, depends on cereals. Green Revolution: An exploitation of structural diversity, which enhances the conversion of water (irrigation) and energy (fertilizer) into food.
For the 21 st century we are asking the green revolution to do more, including: Food for the additional one billion people every 15 years. Over nine billion by 2040? Feed for animals: protein for an emerging middle class . Fuel for more bio-energy.
12 Corn (bushels * 10 9 ) 10 8 Pre-Green Revolution Carrying Capacity Post-Green Revolution Carrying Capacity Green Revolution Carrying Capacity Decadenal percentage change 6 10 10 4 3 (Not including ethanol) 2 Global Population (billions) 8 8 0 End of Green Revolution, ~2005 Wheat (bushels * 10 9 ) 2.5 6 Needed by 2050 6 2 2.0 Estimate of Carrying Capacity, 1970 4 1.5 4 1.0 2 2 0.5 1 0.0 % increase in population 0 0 0 500 1000 1500 2000 0 500 1000 1500 2000 0 500 1000 1500 2000 % increase in cereal production 0.25 Rice (cwt * 10 9 ) 0.20 Year (AD) 0 0.15 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 0.10 Year 0.05 0.00 1995 2000 2005 2010 2015 YEAR
Atmospheric CO2 Eh?
I. An indirect effect of rising carbon dioxide: warmer temperatures. Gas % Nitrogen (N 2 ) 78.1 Oxygen (O 2 ) 20.1 Argon (Ar) 0.93 Carbon Dioxide 0.04 up to (CO 2 ) 0.100 Water (H 2 O) 0.05 to 1.00 No H 2 O and CO 2 ? Surface temperature would be – 18 o C. With H2O and CO2? Surface temperature is 15 o C.
Physical Consequences: Temperature Beware of Averages.
H 2 O vs. CO 2
Less temperature increases where water vapor is high, more precipitation. Greater temperature increases with latitude or altitude; winter vs. summer. Increased desertification, increased drought. Rising sea levels from increased polar and glacial melt.
Plants are essential to life. Light Nutrients Water Carbon Dioxide The rapid increase in atmospheric CO2 will alter global plant biology.
• CO2 is a fundamental resource for plant growth. • Not all plants are beneficial to human society. • Not all plants respond the same way to a resource. • Differential plant response will affect plant-to- plant interactions, competitive outcomes.
Climate, Water and Food Beer = 20-40 gallons Potato = 20-30 gallons Slice of bread = 20-30 gallons Salad= 40-900 gallons Steak= 2500-5000 gallons 75% of fresh water is used in agriculture.
Irrigation: The Colorado River
Other rivers that no longer flow to the sea. Because of diminished snow and ice, river flows will diminish over time, even as rising Temperatures necessitate more water for agriculture.
Where else does agriculture get its water? Aquifers Globally, all countries are using ground water at a faster rate than it is being replenished. This rate is expected to increase with warming.
Where does agriculture get its water? Rainfall: Too Little.
Production: Water, climate and cereals. Global Rice and Water Use. • Rice supplies the bulk of calories for the world’s poor. 100 80 60 40 20 0 Paddy Remainder Rice production
G.E.M.----G x E “old” vs. “new” Wheat vs. Sorghum?
G.E.M.----E x M Capture and Use: Increase resiliency.
E x M for rice: Water and Irrigation. Rice can be seeded directly, then irrigated, using different techniques such as AWD. Adoption of DSR in China Flooding reduces weed competition, but requires large inputs of water DSR Cultivation (Ha x 1000) 800 Jiangsu Province And labor. In addition, flooding can Zhejiang Province exacerbate methane emissions. 600 400 200 0 1990 1995 2000 2005 2010 2015 Year
CLIMATE AND FOOD SECURITY Water is indispensable for agriculture. Yet, it is clear that climate change will significantly impact water availability. Such availability will impact rice production, but the long-term consequences are not clear. G x E x M as one opportunity. What about Carbon Dioxide?
Can we select for CO 2 responsiveness? Vegetative Biomass Seed Yield * * * * * * * AR-1995-StgS AR-1995-StgS DJ123 DJ123 * * Geumobyeo Geumobyeo IL 43-1-2 IL 43-1-2 * * IR64 IR64 IR78049-25 IR78049-25 * IRGC105491 IRGC105491 Jefferson Jefferson 29/21 o C 29/21 o C Nipponbare Nipponbare _ _ Shirkati Shirkati TeQing TeQing X = 0.43 X = 0.42 WAB56-104 WAB56-104 -1.0 -0.5 0.0 0.5 1.0 1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 Relative Stimulation (E-A)/(A) Wang et al. 2016, Global Change Biology, 22:2260
CO 2 and temperature and yield: Making things worse? Seed Yield with Increasing Temperature Percentage of filled spikelets in rice * * * 100 A. C. B. * 90 * H 2 O 80 _ _ _ CO 2 X = -0.25 X = -0.06 70 X = 0.12 * 60 * Ambient CO 2 * 50 Elevated CO 2 * * * 40 * 34/26 o C+T floral 29/21 o C+T floral 34/26 o C * * * 28 29 30 31 32 33 34 35 36 -1.0 -0.5 0.0 0.5 1.0 1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 Air temperature ( o C) (E-A)/A Matsui et al. 1997, Field Crops Research 51:213
Don’t weeds respond to CO 2 ? Wild vs. cultivated rice Relative yield of seed, Stuttgart:Clearfield a 20 300 µmol mol -1 400 µmol mol -1 300 µmol mol -1 CO 2 a 5000 Seed Yield (g m -2 ) 500 µmol mol -1 400 µmol mol -1 CO 2 b 15 500 µmol mol -1 CO 2 4000 b a 10 3000 c b c 2000 5 c 1000 0 0 8 plants m-2 16 plants m-2 Clearfield 161 Stuttgart-S "red" Biological Consequence: As carbon dioxide increases, red or weedy rice responds more. Consequently cultivated rice yields decline.
Differential Response to a Resource. A comparison of wild and cultivated rice lines. Wild biotypes vs. cultivated rice. 8000 Cultivated rice lines 300 ppm Wild or red rice. 6000 ~300 ppm CO2 100 Seed yield (g plant -1 ) ~400 ppm CO2 4000 Leaf area (cm 2 per plant) 80 60 2000 40 0 20 8000 400 ppm 0 6000 Clearfield Stuttgart-S 4000 Two different selection forces. 2000 What can weedy rice teach us 0 about adaptation to climate change? Total biomass at 55 DAS
U SING GENETIC DIVERSITY TO ADAPT TO CLIMATE CHANGE "4484" "Cl-161" 300 * * 200 100 Seed Yield (g per plant) 0 * 300 "Stg-S" "M204" * 200 * 100 0 29/21 31/23 33/25 29/21 31/23 33/25 Day/Night ( o C) Ziska et al. 2014 Functional Plant Biology 41:236. Can our “worst” weeds be our best hope for adapting to climate change?
How are weeds adapting? "4484" "CL-161" "Stg-S" "M204" 70 70 29/21 o C 29/21 o C 29/21 o C 29/21 o C 60 60 Ambient CO2 Ambient CO2 Ambient CO2 Ambient CO2 50 50 Elevated CO2 Elevated CO2 Elevated CO2 Elevated CO2 40 40 30 30 20 20 10 10 0 0 70 70 31/23 o C 31/23 o C 31/23 o C 31/23 o C 60 60 Number of tillers 50 50 40 40 30 30 20 20 10 10 0 0 70 70 33/25 o C 33/25 o C 33/25 o C 33/25 o C 60 60 50 50 40 40 30 30 20 20 10 10 0 0 10 20 30 40 10 20 30 40 10 20 30 40 10 20 30 40 Days after sowing (DAS)
Adapting Yield to CO2 and Climate: Next Steps. 1.2 "4484" 1.0 "CL 161" Seed Yield (E-A/A) R = 0.81 "M 204" "Stg-S" 0.8 0.6 0.4 0.2 0.0 1.0 1.2 1.4 1.6 1.8 Tillers 600 : tillers 400 at 30 DAS
Koshihikari Fe Liang You 84 Takanari Wuyunjing21 Wuyunjing23 Yangdao 6 Yliangyou Yongyou Zhonghua Koshihikari Zn Liang You 84 Takanari Wuyunjing21 Wuyunjing23 Yangdao 6 Yliangyou Yongyou Zhonghua -25 -20 -15 -10 -5 0 Percent decline relative to ambient
Change in vitamin content. Asian RIce Koshihikari Vitamin B1 Vitamin B2 Tocopherol Percent Increase (relative to ambient CO2) Liang You 84 30 Takanari Koshihikari 20 Wuyunjing21 r 2 = 0.82 P<0.001 Tocopherol Liang You 84 Wuyunjing23 10 Yangdao 6 Takanari Yliangyou Vitamin B6 Wuyunjing21 0 Yongyou Wuyunjing23 Zhonghua -10 Vitamin B1 Yangdao 6 Vitamin B5 Koshihikari Vitamin B5 Vitamin B9 -20 Yliangyou Vitamin B2 Liang You 84 Yongyou Takanari -30 Vitamin B9 Wuyunjing21 Zhonghua Wuyunjing23 -40 0.00 0.05 0.10 0.15 0.20 Yangdao 6 0.25 -20 0 20 40 60 Yliangyou Percent change relative to ambient. Ratio of Molecular Weight (N to Vitamin) Yongyou Zhonghua -60 -50 -40 -30 -20 -10 0 -60 -50 -40 -30 -20 -10 0 Percent decline relative to ambient.
Biological Consequences 1. The increase in CO 2 , of an by itself, will also significantly impact crop yields. It cannot be assumed that such an impact is positive. 2. Because increasing CO 2 affects transpirational cooling, higher temperatures may result in greater canopy temperatures and increased sterility. 3. Weedy rice overall may provide a unique set of germplasm that could be used to adapt cultivated rice to climate change through selection. 4. There is substantial evidence that CO 2 per se, will significantly affect cereal quality, including vitamin deficiencies in rice. Such impacts appear to have little intraspecific variation.
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